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The Powder Post Beetles Menace and How to Control It

powder post beetles

Powder post beetles are so labeled that because they reduce wood to a consistency that is similar to powder. The feeding and infestation are so severe that the wood like consistency is achieved at the larval stage. The degradation of the attacked wood happens due to either heavy infestation or repeatedly attacking over a long period. The beetles that fit into this category belong in the Bostrichidae, Lyctidae, and Anobiidae families. Lyctids are the ones that are categorized as the real powder beetles. On the other hand, Bostrichids can be categorized as false given that they differ heavily from the other families not only regarding appearance (because the adults look different) but also the size of the holes they use to exit the wood. Anoobiid is one of the most common beetles. They have a head that is similar to a hood. All these beetles are particularly dangerous because of their ability to breed in the wood or re-infest.

*  Identification and Life Cycle

What does a powder post beetle look like? To eliminate them, one must first invest in the knowledge of powder post beetle identification. Most of these beetles are average in size. The lyctid, in particular, is reddish, almost brown to black. They range from about 1/32 to an eighth of an inch long. 

The outstanding characteristic that they have is that the antennal club is segmented into two. Unlike the other families, the head of the lyctids is visible from above. Anoobiid, on the other hand, have bodies that range from 1/16 to an eighth of an inch long that are reddish brown to black, and cylindrical and slender in shape. Unlike the lyctid, the head is bent downwards into a hood-like posture. Its antenna has many segments, almost 11 in number. The last of these beetles Bostrichid is 1/32 to 3/8 inches long with a body that is reddish brown to dark brown. The thorax has an appearance that is rough, almost like sandpaper, and the body is cylindrical. The forewings are hard and known as elytra. The tips of the elytra are pitted and concave. Unlike the Anoobiid, the head is not visible from above, but it is also bent downward. The antennal club is divided into three or four segments. The larva of the powder post beetle usually develops inside the wood. This makes it unavailable for any identification that you might want to do. They are also very similar to other species making it very difficult to distinguish even when it comes down to the simple matters of differentiating powder post beetles vs. termites. The larvae are usually grub-like with a body that is C-shaped with a particular enlargement at the thorax area. The body is yellowish-white while the head is brown.

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The powder post beetle life cycle is similar to that of other insects. The length of the egg to adult development of the powder post beetles is heavily influenced by the nutritive content of the wood and surrounding environmental conditions particularly the relative humidity and temperature. The limiting factors to the development are the starch content and wood moisture. Amongst the powder post beetles, lyctids have the shortest life cycle. The bugs mostly generate one generation every year, but in favorable conditions, more than 3 generations can be produced. In unfavorable conditions, the larval stage can take up to 4 years. For anobiids, it takes 5 years while one year for Bostrichids. The beetles are particular about where they lay their eggs and make sure it is on bare unfinished wood. The damage that is caused on the wood starts from the larval stage since it feeds on it. During the feeding, a tunnel is created that eventually comes with powdery frass, which is the excrement. The development, as well as the tunneling, occurs on the surface of the wood. The pupation of the beetles occurs when the larva is grown fully. This stage takes several weeks or even months before the adult is fully formed. After achieving the adult stage, the beetle emerges through a hole that it cuts on the surface of the wood. The hole is often made by either the adult or a full-grown larva. If the larva makes it, it often retreats to an enlarged pupal chamber when it reaches the stage of being fully-grown. It then plugs the hole with powder post beetle frass and also wood fibers. The adult finishes the process by removing the plug. The adult powder post beetles only live a few weeks after the pupal stage. They are not easily observable since they are quite small. During the periods of April and July, they often congregate in places where there is light and windows.

*  What Damages Do They Cause?

The powder post beetles damage is often intensive. When wood is heavily infested by these powder post beetles, it is reduced immediately to a powdery mass. The surroundings of the wood become thin shells that are heavily perforated and visible holes that are rather small.

The most common damage that is easy to detect is small exit holes that have frass in powder form sifting through them. Most people are likely to see the evidence of the damage caused on the wood rather than seeing the beetles themselves. The holes usually vary depending on the families that the beetles come from. For Bostrichid, the exit holes are always significantly larger than that of the lyctids. The diameter always ranges from about 0.09 to 0.28 inches and can also be smaller. The powder or the frass that is sifted through the holes is very useful when it comes to identification. For the lyctids, the powder comes out very fine in texture. It is loosely packed in the tunnels and also has a feel of talc when rubbed between fingers. For the Anobiids, the frass is also similar to powder but with a feel of grit mostly dependent on the type of wood that has been infested. When it infests softwood, the frass is also loosely packed but with elongated pellets that are lemon-shaped since it retains the gritty consistency, while in hardwoods the powder is fine without pellets but very packed in the tunnels. For Bostrichid, the frass sticks together in a coarse powder form and is very tightly packed.   

*  Types of Wood Attacked

Powder post beetles are known for damaging a range of wood products. When it comes to structures, the beetles damage joists, wooden rafters, paneling, windows, plywood, flooring, molding, and doorframes. They can also go further to damage furniture, picture frames, crates, gunstocks, tool handles, ornamental objects, baskets, and fishing poles. Early detection is advised since it avoids more serious damages. The Lyctids only target hardwood especially the ones that have large pores or vessels.

The reason that the pores must be large is to allow the female bug to insert its eggs. The wood has to have more than 3 percent starch, which is an essential nutrient for the lyctids. They rarely infest wood that is older than 5 years. The highly susceptible hardwood is ash, oak, and mahogany. The Lyctids also infest the low density and lighter colored tropical hardwood such as the banak and obeche. Anobiids, on the other hand, are more common than the Lyctids and even Bostrichids. They attack both soft and hardwood. However, they are known to cause more damage to the hardwoods in comparison to the softwoods because they have a higher content of nitrogen. The woods that are often attacked are the beech, maple, pine, and poplar. The anobiids also do extensive damage to any wood that has a very high moisture content. Most of the infestation occurs in wood that is untreated and unfinished. It also occurs on wood that is in areas that are poorly ventilated like basements. Softwoods are often victims because they are used in building construction so are susceptible when they are exposed. If the wood is not exposed to central heating to keep the moisture out, then it will end up with a lot of infestation. For Bostrichids, infestation mostly occurs in the tropics. They attack both the seasoned and unseasoned hardwoods. Starch is the main nutrient content that the Bostrichids go after. They do not re-infest wood when they dry out.

*  Determining Whether an Infestation is Active or Inactive

The attack on woods usually happens months or years before there is any detection of the holes that are later formed by the emerging adults, which brings forth the question of how to tell if powder post beetles are active? Exit holes on the surface of wood are the first key indicator that the infestation is still ongoing or it occurred. However, in some instances, the powder pest beetles die out of their own accord. This makes it very important to figure out whether the infestation is active otherwise one stands to lose a lot of money and time on a control measurement that is not necessary. Most control measures are lengthy and difficult so you should first find a guarantee.

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When it comes to determining whether an exit hole is new or old is very difficult. However, there are few characteristics that one can use to tell them apart. An abandoned exit hole usually has a weathered appearance of the general of the adjoining wood while one that is still active does not have a weathered appearance.

Most active infestations have a powder that is light colored that is somewhat the color of fresh cut wood that can be spotted being sifted out from the holes. The powder often accumulates in a pile just below the holes. Nonetheless, it is also important to pay attention to the piles that form given that vibrations can extricate powdery frass from galleries of the old larval. Inspection of the piles will help you know whether it is old, if they are covered a film of debris or dust, the infestation is likely inactive. It might also help a great deal if the existing holes can be marked with tape to seal them off completely or avoid future confusion. You can also note the activity mechanically by sweeping the piles once they accumulate and wait to see if there will be any other accumulation that will prove there is activity. The summer and springs are the best seasons and time to re-inspect the exit holes. This is mainly because the adults emerge in April and July. It is possible that new exit holes might not appear in winter or autumn since the pupal stage depends on the favorability of the surrounding conditions.  

How to Get Rid of the Powder Post Beetles

a) Prevention and Exclusion 450

Wood processing operations normally remove powder post beetles infestations in lumber and also through kiln drying. The kiln dried over a period of 8 hours long at 80 percent relative humidity with over 130 to 140° F. During any new construction, it is advisable to use kiln-dried lumber to actively avoid infestation. The main question you are asking may be, how do you get powder post beetles? You should know the infestation normally occurs from poor storage of wood in the home. If the stored wood is improperly dried, it will harbor powder post beetle larvae or even eggs. This applies to the paneling, lumber, flooring, and even furniture. The best thing to do in a situation is not to use any of the wood that has signs of infestation from poor storage and has signs of improper drying. A greater magnitude of infestation occurs when old lumber is taken out of an outdoor woodpile or even a bam and used for remodeling a house or improving on building and paneling. The powder beetles only lay their eggs on bare wood or unfinished so most of the prevention mechanism should go into these types of surfaces. For some, unique powder post beetles such as the Bostrichids can easily be prevented by simply removing the bark edges of the wood. It is the place they mostly choose to lay and harbor their eggs. The powder post beetles that are seen emerging from finished furniture implies that the pests were previously present in the wood before the construction occurred. When you spot powder post beetles emerging from finished items or structures, the possible technique that you can use to prevent future re-infestation is to seal off the holes they emerged from. This is because the beetles lay eggs before leaving the exit holes. By sealing off the opening, you will be actively preventing future generations from surviving. The anobiids infestation mostly occurs as a result of the beetles flying in from outdoors or the eggs being carried into the household through firewood. If you are wondering how to get rid of powder post beetles in hardwood floors, it is probably because the anobiids are the ones that have invaded your space. The best way to actively prevent this is to use fitting screens for the windows to ensure they do not get in and also place them on the doors to block out the possibility of flying beetles entering.

b) Moisture Reduction

Most of these powder post beetles have specified moisture levels that can sustain them and help them develop. Without the specified moisture content, they will either take too long to develop or not survive at all. Most of the post powder beetles cannot survive any moisture content that is below 15 percent. An air conditioning system or central heating is known to reduce the moisture to 12 percent and below. This creates unfavorable conditions for the survival of the beetles especially the anobiids. During construction, it is necessary to install a vapor or a moisture barrier in the crawl space of the site or structure. Covering the surrounding soil also plays a major role in reducing the moisture content. The cover should be polythene sheets that are four to six mil. For already existing infestation, the covering up will also actively prevent the beetles from spreading upwards into the walls and the upper places in the building. The moisture barriers also play a good role in preventing re-infestation because it restricts the spread and removes any moisture that might attract other beetles. Increased ventilation also helps in reducing the moisture content in the damp spaces. This can be easily achieved by installing foundation vents. For every 150 square feet there can be one square foot of vent where a vapor barrier is not presented, and for every 300 to 500 square feet, there can be one square foot of vent where there is a vapor barrier. The vents must be kept open at all times to achieve maximum efficiency. All the vegetation that covers the vent should be removed as well.  

c) Wood Replacement

In case you are wondering how to get rid of powder post beetles naturally, wood replacement is one of the best solutions. When the infestation is localized in places that are removable, it is best to remove the wood and replace it with another one that is healthy. This applies to flooring, paneling, and molding. However, sometimes this is not effective as if the infestation already spread. At this point, it is advisable to use other methods such as chemical control.

d) Subzero Temperatures

When the powder post beetles occur in small infestations, it is possible to eliminate them using subzero temperatures. This especially applies if the infestation has occurred in a movable item. The beetles, their larvae, and eggs cannot survive at subzero temperatures. You can place the movable items in freezers for over 48 hours. This would help immensely help in powder post beetle damage repair.

e) Insecticide Treatments

Chemical control is very effective when dealing with powder post beetles. It can easily be dealt with if you apply a liquid insecticide on the surface of the infested wood. This especially helps when the infestation has occurred on structures. The most effective component is boron. You should prioritize shopping for boron-based insecticides when trying to eliminate the bugs. It should be easy if you follow the instructions. For most of the unfinished wood surface, the key thing to do is apply the product on the surface. It will act fast by penetrating the wood and manage to kill the larvae. Killing the larvae is very effective given that the adults rarely live for long and the major cause of damage is the larvae. The boron also actively prevents re-infestation. Alternatively, the liquid insecticide can be administered by use of pressure pumps through injection to the small holes of the damaged surfaces. When the wood is actively prevented from moisture by heating and air conditioning, the insecticide will have a very long lifetime and affectivity. Copper compounds are also very effective, but they are not as efficient as the boron because they only penetrate a few inches, probably an eighth, into the wood. A pyrethoid can also be used since it has a very high level of toxicity. When injected into the wood it will only take a few moments before the larva elements are killed. The efficiency of fumigation is very high since it kills off all the life stages of the beetles that are in the wood. Compared to the other methods, one might find fumigation more expensive especially since it gives no guarantee of future protection from re-infestation. If the infestation is small, fumigation is the easiest method to use.

The use of Diatomaceous Earth is also advised for powder post beetles treatment. It usually comes in the form of a powder. The powder is achieved through the grounding of diatoms. The major technique or tactic that the powder uses is the dissection of the exoskeleton and dehydrate the beetles causing its death. This mostly applies to the larvae since the adults have a hard exterior. This can be achieved by spreading the powder on the surface of the wood and sprinkling it into the holes that have been dug by the bugs. The DE might not help fully if the infestation is huge but is very effective for smaller ones given that it prevents the next generation from maturing.

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